Photon Collider at TESLA

The basic scheme of the Photon Collider is shown below. Two electron beams of energy E_0 after the final focus system travel towards the interaction point (IP) and at a distance b of about 1-5 mm from the IP collide with the focused laser beam. After scattering, the photons have an energy close to that of the initial electrons and follow their direction to the interaction point (IP) (with small additional angular spread of the order of mc^2/E_0 < 10^{-6} - 10^{-5}, where they collide with a similar opposite high energy photons or electrons. Using a laser with a flash energy of several Joules one can ``convert'' almost all electrons to high energy photons. The photon spot size at the IP will be almost equal to that of the electrons at the IP and therefore the luminosity of gamma-gamma, gamma-electron collisions will be similar to the ``geometric'' luminosity of the basic e+e- beams (positrons are not necessary for photon colliders). To avoid background from the disrupted beams, a crab crossing scheme is used, Fig. b with the crab crossing angle about 30 mrad. In this case final particles do not hit focusing quadrupoles.

Properties of photon beams: spectrum, polarization, e+e- pairs and nonlinear effects in conversion region

Physics: gold-plated processes

Cross sections for some processes in gamma-gamma, gamma-e collisions

Parameters of the Photon Collider at TESLA

Luminosity spectra in gamma-gamma and gamma-electron collisions at TESLA

Some slides:

1) V.Telnov. Photon Coillider at TESLA (review of the TDR), talk at 2nd Int.Workshop on High Energy Photon Colliders, FNAL, March 13-17, 2001

2) V.Telnov. The Interaction Region for gg, ge collsions at linear colliders, talk at INSTR02 (Feb.2002), NIM A 494 (2002) 35

Last updated by V. Telnov on 22-July-2004